Electropneumatic brake system



Nov. 13, 1945. Q H|NES ELECTRO-PNEUMATIC BRAKE SYSTEM Filed July 1, 1944 2 Sheets-Sheet 1 l l i l l (\J n INVENTOR. BY GLaudcMHines ATTORNEY Wm mw @w @w Nov. 13, 1945. c, M, HMS 2,389,052

ELECTED-PNEUMATIC BRAKE SYSTEM Filed July 1, 1944 2 Sheets-Sheet 2 INVENTOR.

GZaudeMffines ,BY z- ATTORNEY Patented Nov. 13, 1945 ELECTROPNEUMATIC BRAKE SYSTEM Claude M. Hines, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa, a corporation of Pennsylvania Application July 1,1944, Serial No. 543,080

\. '7' Claims.

This invention relates to electropneumatic brake systems, and more particularly to a fluid pressure actuated brake equipment for a railway train embodying electrical means controlled at the leading vehicle or locomotive for expediting and rendering uniform the application and release of the brakes throughout the train.

Experience has indicated that both automatic air brake systems and electropneumatic brake systems of current design can economically be used only on trains that are definitely limited in length. Safe control of the slack action between cars necessitates rapid propagation of the application of the brakes uniformly throughout a long train, so that the braking forces on the individual cars can be increased at substantially the same time. It has been determined that the maximum propagation speed theoretically possible for airbrake' systems has already been closely approached by development of existing equipments, and that further increase in the length of the trains equipped with standard electropneumatic brake apparatus would require recourse to bulky train cables of large cross section and provided with special insulation, in order to overcome the effects of voltage drop between the sources of operating current on the locomotives and the brake controlling magnets on the cars. motive design in combination with roadbed betterments are to be exploited to the greatest advantage, it becomes expedient to extend the present limits on the length of trains by devising new means facilitating exact and rapid control of the airbrakes on railway vehicles, without unduly increasing the cost of manufacture and operation of the equipment.

It is an object of my invention to provide an improved electro-pneumatic brake equipment having electronic control means operative to govern energization of local circuits connected to magnet valves on cars in a train, in accordance with variations in voltage impressed on a grid control circuit common to all electronic control devices in the system.

Another object of the invention is to provide an improved electropneumatic brake system for railway service comprising fluid pressure responsive means for applying the brakes on units in a train, and electronic means constructed and arranged to control operation of the fluid pressure responsive means from the locomotive.

A further object of the invention is to provide electronic brake control means designed for utilization of commercially available elements such If recent improvements in 1000- as electronic tubes, and constructed in a form suitable for installation in existing railway brake systems.

Other objects and advantages of the invention will be apparent in the following more detailed description thereof, taken in connection with the accompanying drawings, inwhich Fig. 1 is a diagrammatic view of an elementary form of electropneumatic brake equipment for locomotives and cars in a train, constructed and arranged in accordance with one form of' the invention; and

Fig. 2 is a similar view of an electropneumatic brake system embodying electronic control features constructed in accordance with another form of the invention.

Apparatus shown in Figure 1 The equipment illustrated in Fig. 1 includes brake apparatus adapted to be carried on a locomotive and two cars in a train, the elements of the brak system being shown in elementary, schematic form. The apparatus mounted on the locomotive includes a brake valve device I, a main reservoir 2, a master controller device 3, a con trol pipe 4, a straight air pipe 5, an application and release magnet valve unit 6, and a brake cylinder 1, which is adapted to actuate the usual bra-king elements associated with the locomotive wheels, not shown. The locomotive equipment further includes a pair of electron discharge devices 8 and 9 of the vacuum type constructed and arranged as hereinafter explained for controlling circuits for energizing the application and release magnets from a local source of electrical energy, such as a battery it. Associated with the master controller 3 is another battery H which is adapted to energize the grid circuits of the respective electron discharge devices.

The brake equipment on each of the cars connected to the locomotive includes the straight air pipe 5 and a supply pipe 12 connected to the main reservoir 2 on the locomotive, an auxiliary reservoir 13, a brake cylinder M, an application and release magnet valve unit I5, a car battery [5,

and electron discharge devices I! and I3, which are preferably of the vacuum type.

The master controller device 3 carried on the locomotive comprises a hollow casing structure having mounted therein a pair of flexible diaphragms l9 and 20, the central portions of which are secured to an axially disposed follower member 2| extending through a central chamber 22. At the outer face of the diaphragm I9 is formed a pressure chamber 23, which communicates by way of a passage 24 with the straight air pipe 5 and, for the purpose of illustrating the invention, with the brake cylinder 1. Formed at the outer face of the diaphragm is a pressure chamber 25, which communicates with the control pipe 4 through which fluid under pressure can be supplied to the chamber for operating diaphragm 20 in opposition to the pressure of fluid in cham- 'ber 23 acting against the diaphragm l9, as hereinafter explained. A spring-pressed abutment 26 is mounted in the casing structure in operative alignment with the end of the follower member 2T adjacent the diaphragm IQ for "resisting. move ment of the diaphragm and follower assemblage to the left, as viewed in Fig.1. Morintedbnth;

ments 28, initial movement of the block 21 to the 7 left serving to separate the contact elements. The block 21 is also operatively aligned with another pair of normally engaged contact elements 29, which are positioned farther to the left,'beyond the contact elements 28, so that'continued movement of the block 21 subsequent to disengagement of the contact elements 28 will serve to disconnect the contact elements 29. As explained hereinafter, the contact elements 28 and 29 are connected for controlling the energization' of suit. able grid circuits for the tubes 8 and 9 on the locomotive, and the respective sets of tubes I1 and I8 on each of the cars in the train, in accordance with operation of the mastercontroller device 3. The latter device is in turn operative in response to manipulation of the brake valve device I, which is preferably of the self-lapping type operable to charge the control pipe 4 to any desired pressure, as determined by the position to which the usual handle is moved.

The application and release magnet valve unit 6 is interposed between the supply pipe l2 leading from the main reservoir 2 and the straight air pipe 5 leading to the brake cylinder 1, and comprises a casing structure having a valve chamber 29 containing a normally unseated release valve element 30 that is movable to its seated position upon energization of a magnet 3|, and a valve chamber 32 containing an application valve element 33, which is normally urged toward a seated position and is operative to its unseated position upon energization of an application magnet 34. The release valve element 30 is arranged to control communication from the brake cylinder 1 and straight air pipe 5 to the atmosphere, while the application valve element 33 is adapted to control communication from the main reservoir supply pipe 12 to the straight air pipe and brake cylinder. The magnet valve units l5 carried on cars on the train are similar in construction to the unit 6 just described. It will be understood that the auxiliary reservoir l3 associated with the equipment on each car is normally maintained charged with'fiuid under pressure from the supply pipe l2 to provide a local volume of fluid under pressure.

The electronic tubes 8 and 9 on the locomotive, and tubes l1 and IS on each of the cars on the train, are provided with control elements or grids connected to common control circuits extending through the train, and are arranged for simultaneous operation to control energization and deenergization of the corresponding magnet valve units of the brake system. The electron discharge device 9 has an anode 35, a cathode 36 and a grid or control element 31, and is arranged to control energization of the release magnet 3| through a circuit which includes the positive terminal of the battery In, a conductor 38, the winding of the magnet 3 I, a conductor 39, the anode and cathode of the tube, and a conductor 40 leading to the negative terminal of the battery. The electronic tube 8 has an anode 4|, a cathode 42, and a controlelement 43, and controls a plate circuit which includes the positive terminal of the battery H], a conductor, thewinding' of the application magnet 34, a conductor 45, the anode and cathode of the tube 8, and return conductor 40 leading to the negativeterminal of the battery. Filaments 46 and 41 of therespective tubes 8 and 9 may be heated through-the medium of a common filament ing of the release magnet 50, a conductor 55, the

anode 5|, cathode 52, and a conductor 56 leading to the negative terminal of battery. Similarly, each electronic tube ll controls the magnet 49 through a circuit including the positive terminal of the battery It, 'a conductor 51, the winding of the magnet, a conductor 58, an anode 59 of the tube, a cathode 60 of the tube, and the return conductor 56 to the negative terminal of the battery l6. The tube I! has a control grid 6| connected in a train control circuit as hereinafter explained," and also'has a heating filament 62 which, together with a similar filament 63 of the tube I8, is adapted to be energized from the battery [6 through a filament circuit in which is interposed a current limiting resistor 64.

The control grid circuits for the electron discharge devices 8 and 9 on the locomotive, and for the electron discharge devices I l and I8 on each of the cars in the train, are established through the medium of three train wires 65, 66, and 61, the grid circuits being energized from the battery ll carried on the locomotive, under control of the master controller device 3. The train wire 61 is connected to the positive terminal of the battery II, and is also connected to the conductor 49 leading to the cathodes of the tubes 8 and 9 on the locomotive, and to the conductor 56 leading to' the cathodes of the tubes I1 and I8 on each of the cars, by way of conductors 61, as shown in Fig. 1. A conductor 69 is provided for connecting the negative terminal of the battery I I to one of the normally engaged contact elements 29 of the master controller device 3, the other contact element 29 being connected to the train wire 65, which is in turn connected through a current limiting resistor 69 to the control grid 43 of tube 8 on the locomotive and also through a current limiting resistor 10 on each of the cars to the associated control grid 6| of the tube I! provided on each car. It will thus be seen that a negative biasing voltage is impressed on each of the grids 43 and 6| in the system, so long as the contact elements 29 in the master controller device 3 remain closed. The negative terminal of battery H is alsoconnected through the medium of conductor 68 to one of the normally engaged contact elements 28 in the master controller de: vice, the other contact element 28 being connected aeeaota to the train wire 66'.- The train wire 66- is con nected to the grid 31 of the tube 9 on the locomo tivethrough the medium of a current limiting resistor TI, and also to the grid $3 of each elec tron discharge tube" to on each car through the medium of a current limiting resistor [2. Consequently solong as the contact elements 28 are closed as shown, a negative biasing voltagewillbe impressed upon the respective grids of tubes 9 and to throughout the train. It will be un derstoo'd that the negative biasing potential thus impressed on the grids of the respective tubes ispredetermined by a proper proportioning of the various elements of the: rid circuits so as to rein der the respective tubes nonconductive while the master controlier device 3 remains inoperative;

In Fig. 1 the brake controlling a paratus is illustrated as conditioned for maintaining the brakes released throughout the train, it being assumed that the brake valve device- I is dis osed in release position for connecting the controi pipe 4 to the atmosphere. The movable elements of the master controller device 3' are thus disposed in the inoperative position, with the normally closed pairs of contact elements 28' and 29 position-ed for maintaining energized the grid circuits for the electron discharge devices included in the eq ipment, as already ex iained. The electron discharge devices thus remain nonconductive, and

since no current is supplied to the application and release magnets of the magnet valve units 6 and Ni, therespcctive valve elements thereof are positioned for venting the respective brake cylinders 1 and M to the atmosphere.

When it is desired to effect an application of the brakes,v the brake valve device I is moved. to an application position for causing supply of fluid under pressure fromthe main reservoir 2- to the control pipe 4 and to the chamber 25 in the master controller device 3, with the result that the diaphragm 20, follower element. 2| and diaphragm is are forced to the left, as viewed in the drawing'. Upo'n initial movement of the follower member to the left, the block 21 thereon is brought into engagement with the extension on one of the contact elements 28 to interrupt the circuit controlled by these contactr elements. As previously pointed out the contact elements 28 are arranged to control the train circuit for supplying the negative biasing potential to the grids of the electron dischargedevices 9- and I8; which are rendered conductive upon removal of the negative charge from the control grids thereof The release magnet 31 on the locomotive is thus energized through. the circuit controlled. by tube" 9 as hereinbefore described, and simultaneously each of the release magnets 5!! on cars through-- out the: train is energized by way of the local circuit controlled by the associated tube to. The respective release valve' elements are consequent ly o erated. to cut-off the atmospheric vent communications for the brake cylinders 1 and M Upon continued movement of diaphragms 20 and I9 and the follower element H of the master controller device 3, the block 21 is brought into operative engagement with the extension of one of the contact elements 29 for interrupting the grid biasing circuit controlled thereby, with the result that the tube 8 on the locomotive is rendered conductive for effecting encrglzation of the application magnet 34, while the tubes H on the cars are rendered conductive for" effecting energiz'ation of the associated application magnets 49. Upon energization of the application mag" nets throughout the train, the magnet valve olementS controlle d thereby are unseated. for eflccting supply or fluid under pressure from the main reservoir pipe l2 to the respective brake cylindots to produce an' a plication or the brakes in the usual" manner.

Meanwlnle, fluid under pressure supplied to the brake: cylinder l by wa 'oi the pipe 5 on the-locomotive also flows iroin that ipe to the diaph r'ag'iil chainher' 23f the master controller device- 3, and the force thuscreated on the diaphragm ts 'substantially" equals that exerted the opposite direction on the diaphragm 20 by control pipe pressure, the diaphragms and rol lower member M are caused to move: to the right, until thehloeli" 21 is carried away from the con'- tact elements 25 to permit reest'ablis'hment oi the grid biasing circuit for each of the tubes 8 and it throughout the train; The: vacuum tube 8 on the locomotive is thus rendered nonconductlve asthe negative biasing voltage is again: impressed upon the: control grid 43 thereof, so that the magnet 3o or? the application magnet valve deviceis once more deenergizc for cutting on iurthcr supply of nine under pressure to the brake cylinder 1. At the same: time, each of tubes H is rendered nonconductlve upon restoration of the biasing potential on the associated control grid of, with: the result that the local application magnet 59' becomes deenergized to en'ect cutoff of the supply of fluid under pressure to the brake cylinder M on the'car;

since fluid under pressure is no longer supplied to the straight air pipe rand the diaphragm chamber 23 connected thereto, further movement of the diaphragmsand follower member 2| of the irlastercontroller device is prevented at this time, the block 21 thus being held stationary while still positioned to maintain the contact elements 28 separated. It will thus be understood that the grid biasing circuit for the respective tuhes 9 and to of the hrake controlling system is still closed, so that those tubes remain conditionedto conduct current for energizing" the respective release magnets 3t and so, reventthe release of any fluid under ressure from the brake cylinders. The electro-pneumatic brake equipment is therefore maintained in a condition tor continuing the application f the brakes in accordance with the redetermine pressure of fluid established in the control pipe 4 by operation of the brake; valve device.

If it is desired to increase the degree of application or the brakes, the brake valve device I ma be again operated to ff'ot further supply of fluid under pressure to the control pipe 4 for again increasing the pressure in the diaphragm chamber 23' of the master controller device,

' whereupon. the diaphragms' and block element 21' are again operated lac-interrupt the grid biasl ne circuit controlled by the contact elements 29 irithe manner herinbefore explained. Each of the tubes a and ll is then rendered conductive long enough to cause energizatlon of the associated application magnets to effect the desired increase in the brake cylinder pressure. when the pressure of fluid in control pipe 5 and diaphragm chamber 23 has thus been further increased to a value representingthe desired for the-tubes 8 andylflzcontrolling the various application magnets through out the train,

When it is desired to effect the release of-the brakes, the. brake valve device l is operated to out 01f the supply of fluid under pressure from the main reservoir to control pipe 4 while venting the latter pipe to the atmosphere, thus causing reduction in the pressure of fluid in diaphragm chamber 25 of the master controller device. Upon reduction in the pressure of fluid acting on the diaphragm 20, the straight air pipe pressure acting in chamber 23 of the master controller device against the diaphragm I9 is rendered effective to shift the diaphragms, follower member 2| and block element farther to the right until the block is carried out of operative alignment with the contact elements 28, which are thus permitted to close the biasing circuit for the tubes 9 and 18 throughout the train. Upon energization of this circuit, which'has already been traced, a negative biasing potential is again impressed on the grid 31 of tube 9, and on the respective grids 53 of the tubes I8 on the cars, so that all of these tubes are again rendered nonconductive. The release'magnets 3| and 50 are consequently deenergized for eifecting release of fluid under pressure from associated brake cylinders 1 and I4.

It will thus be understood that by employing the master controller device 3 on the locomotive for controlling grid biasing circuits for the electronic devices controlling the brakes throughout the trains, the electropneumatic brake system can be 'equippedto enable an engineer to effect operation of all brake controlling devices throughout the train accurately and-substantially instantaneously, regardless of the length of the train. The current flowing in the grid "biasing circuits is'very low in comparison to the current required for energizing the brake controlling magnets from the head end of a train; consequently there will be substantially no voltage drop in the train wires constituting these grid circuits, and practically no limit on the length of the trainso far as the brake system is concerned. All elements of theelectronic control equipment may be of a standard design readily obtainable without .requirement of special construction. The air brake system with which the electronic control apparatus is associated may be provided with all the features of construction which have heretofore proved successful in the control of the brakes on heavy, high-speed trains, with the result that the advantages of such an air brake system will. be augmented and given increased effectiveness due to the sensitive control afiorded by the electronic means.

Apparatus shown in Figure 2 InFig. 2 is illustrated substantially the same elementary form of fluid pressure brake system as that already described in connection with Fig. i in conjunction with an electronic means for controlling the brakes on each unit in the train embodying the invention in a different form. Elements of the apparatus shown in Fig. 2 which are similar in construction and function to those shown in Fig. 1 have been identified by lik eference characters, and need not be again described in detail. 'As-shown in Fig. 2, the electron discharge device or tube 9 on the locomotive, and the tube [8 on each of the cars in the train, are constructed and arranged to constitute the means for controlling both of the associated application and release magnets of the fluid pressure brake equipment, while the master controller device 3 on the locomotive is in this case adapted to eifect-energization of the single control grid circuit of the train at different potentials in efiecting the desired control of the brakes.

According to the invention as disclosed in Fig. 2 0f the drawings, the brake controlling equipment on the locomotive includes, in addition to the devices which will be recognized as having been described previously, a voltage divider having an adjustable minimum voltage tap l3 and a similar maximum voltage tap 14. The voltage divider is arranged in conjunction with a contact element of the master controller device 3 for controlling energization of the grid biasing circuit for the electron discharge device 9 on the locomotive, and the electron discharge device I8 on cars of the train, which devices in this case constitute the sole circuit controlling means for both the application and release magnets controlling the pressure of fluid in the respective conductor 16, magnet 3|, a conductor 11, anode 35, cathode ,36 and conductor 18 connected to the negative terminal of the battery. The plate circuit for each of the tubes l8 on cars in the train includes the positive terminal of battery IS, a conductor 19, magnet 49, a conductor 80, magnet 50, a conductor 8|, anode SI of the tube l8, cathode 52, and a conductor 82 leading to the negative terminal of the battery.

In operation, while the brakes are released, the elements of the master controller device 3 are positioned as shown in Fig. 2, so that the respective pairs of contact elements 28 and 29 are disposed in their normally engaged positions. A negative biasing potential. is consequently impressed on the control grid 31 of the tube 9 of the locomotive, and also on the control grids 53 of the several tubes l8 on cars of the train, through a common grid circuit whichdncludes conductor 61 leading from the positive terminal of the grid supply battery II, the respective cathodes of the tubes, the control grids, conductor 66, the contact elements 28, and a conductor 83 leading to the maximum voltage tap 14, the portion of the voltage divider resistance preselected according to the position of the tap, and the negative terminal of the battery I I. It will be understood that each of tubes 9 and 18 are of the vacuum type, and that with the respective control grids thereof thus subjected to a maximum negative potential, the tubes are maintained substantially nonconductive, so that neither of the associated application and release magnets of the brake controlling valve device are now energized. The brake cylinder on each unit of the train is thus connected to the atmosphere through the corresponding release valve portion of the brake controlling magnet valve device.

When it is desired to effect an application of on the respec i e grid elements or th ith s is thus reduced to a value prese e ted acc rdin 9 t e pos tionin .of th m nimum volta e ten :13 on th volta e d vider. Joy wayof th rid rincludes the osi ive te m na of the bat ery H, conductor 63, h ca hode elemen s or the tubes, the grids the e t conducto 6.6, the st l engaged pair r contact e ements 23 the master'con roller device 3, a conduc or 84, the tap 1.3 and a portion of the vo ta e d vider resistance between the t p and the ne at ve terrnnal of the battery- It will he r d rsteod that the various elements of the e ectronic cont ol a paratus form n part of the b ake c ntroll system are so propo tioned that upon the r auction in grid biasing potentia e fected as Just explained, each .01 the tubes 9 a d i8 s render d effective to passe limitedzam hht oi cur ent wh ch will be of snflie ent value toenereize the release ma net or the associated brake eontrllin =va ve device to sheet closur of :the a soeiated release alve without ener izin the adiacent applicat on m net to the de ree heces sary fo ope ation of, the appl cation valve eon- ;trolled thereby. Thus by way of explanation, th tube 9 on the lo omo ve s r nder d responsiv to the part al w thdrawal of th B i htive hissing volta e of the grid .31 for passin limited current throu h its plate cir u t which includes the pos t ve tetihinal of the batt y I 0. conductor 15. ma net Win in 34, condu tor ma net winding 3.], conduc or 1 plate 35, .eathode an conductor 18 leading to the ne ative terminalof thebattery, cur ent, whi e too lowpto cause nnseating of the applicat on "valve 33, ener izes the releas magnet wind n -31 sufficientlyeto effect closu e of the re ease valve element 39, cutting off the communication between the brake cylinder 1 and the atmos-' pphere. 7

continued movement of the diaphragms 2. and t9 and of rod 2| and block .2] to the left quickly efiects opening of the contact element 29, thus removing the remaining rid biasin vol age of the re p ctive eontrolsrids f, the tubes throh hoiit the train, for rendering the tubes conductive ofta current -.s1iffiroient to ener size the. nations application ma nets alo e-with :the release magnets. .Qn'th 'locQmotii/e, the snasnet winding 34 is thereby energized slit.- .fieiently tonnseat therapp ication valve element inland fluid underpressure is then supnlied --iron1 the supply pipe 12 to the brake cylinder 1. andeestraight air pipe operation is re,- .pea ted on each throughout the efliecte .sing a uniform and instantaneous app ication of the :pr-akes,

The increased pressure of fluid in straight air pipe 5 then becomes effective in chamber 273 of .the vmaster controller device 3 to iorcedia- .phragm 19 to the right, in opposition to the pressure of fluidacting in chamber .25 against 'therdiaphragm 20, until the block :21 is moved away from. the contact elements 29, which are men permitted to assume their normally engaged position. Ther is thus impressed on the controlgr-id elements throughout the train the grid. biasing voltage necessary to render'the respective tubes conductive of the limited current which, as already explained, is sufiicient .to maintain the release magnets. energized :whiIe racing insuificient to cause efiective .energization .piiahe application magnets. As a result of the partial deenergization of the application 7 magtheapplication valve elements controlled he eby a e re urn d to th r closed pos tion for setting off hirth u p y o lu d unde esto th brake cyl nd rs- Ih b ake t nro ine a parat s is thus condit n or mainta nihe e bra-hes appli d th ugh ut the a n aster-dance :tv h th pr d ermin d pressu e o fluid stabhmed the co t ol pi e 4 .by the a tral e era ien of the bra e a e de ice.

"Ierelease the brakes. th en ineer may ope ate the brake valve device I fo vent n u d under pressure from the control piped wherenpon the -n e sn e of fluid remaining in d .-ph: aern-ehamber 2 .ot t mas e cont oller d vised rendered e eet v to shift the o ect d na roi el anhr sm o the rig t, s viewed in Fi nit-t l the hlecl; 1 is carried o t Of o erathe alignmen th the conta t me ts 8- Wit coh aetelem ts 28 thus pe m tted to assnmeth i normal y c o ed position, the grid biasing ch t contro led 7 the eby is re stabished,- ni-th the re ult th he maximum grid hiasi potential is rest red eh ea h o the troi ids of t bes th u out th tra n re ns the tubes .neneent uetive fo e e z ng t ass c ated release ma ne s in dd t on o he app cation ma net va e e va are thereie e simultaneously O era ed o lease flnidnnder p e sur t m th brak cyli ders to efieet the re ease o the r k in the u ual manner.

From the iereeoihs t will be a p re t a ith the electronic contro app rat s di c os d in :Zxthe flu d press e brake t ro u a one m y b con rol d accu a ea h ope ti n of th br ke valve de ce on he comot induc ng in a taneous r sponse by he brake ontrollin equ pm nt on each un t t ugho the :By the u e o vacuum e e c r t lees o erative to conduct curren propo t o to the de ree of g id bias vo a e, t e n m o train w res r qui ed can e r d d t wo, While the electronic apparatus 9 eac tra n n t y consist of a sin e ube with th ecessary cir u s, ncludin a tra n len th id cir ui adapted to carrya ne i ble cur ent to produc theerid biasi yolt ees. A th u h only an el lmentaryiiormoi'flu d p essure brake system has been disclosed "ihieonhe ti n with my improved electronic bra e controllin apparatus, it wi l b understood that the features at the invent on may 'be incorporated in more elaborate, electropneu- :matic' brake systems, such as those with which existing-railroad cars havebeen equipped 'Having now described my invention, what I claim as new and desire to secure by Letters Patient is:

1. An electronically controlled electropneumatic braking system comprising means for effecting application-and release of the brakes ineluding an application magnet and a release magnet, a control pipe chargeable with fluid under pressure preselected according t any desired degree of application of the brakes, a master controller device includin fluid pressure ac 5 tuated switch means responsive to relative changes in pressure of fluid in said control pipe and an opposing pressure measuring the degree vo1 application of the brakes, an .eleotron discharge device including a control member and an anodeecathode circuit forenergizing said ap- -plication magnet, another electron discharge device including a control member and .anodeecat-hode circuit for energizing said release magnet biasing circuits. connected to said control members, respectively, and normally conditioned by said master controller device to impress a negative potential on each of said control 'members for rendering each electron discharge device noncoriductive in maintaining the brakes released, said master controller being operative upon an increase in control pipe pressure first to interrupt the biasing circuit for the electron discharge device controlling said release magnet and then to interrupt the biasing circuit for the control member of the electron discharge device for said application magnet. I I

2. In a brake system of the type having a brake cylinder operative to effect application of the brakes according to the pressure of fluid supplied thereto, the combination of application magnet valve means normally conditioned to cut oil the supply of fluid under pressure to the brake cylinder and operative when energized to cause fluid under pressure to be supplied to the brake cylinder, release magnet valve means normally conditioned to efiect the release of fluid under pressure from the brake cylinder and operative when energized to cut oil the release of fluid under pressure from the'brake cylinder, electron discharge means adapted to be conditioned to selectively cause simultaneous deenergization of said application and release magnet valve means, energization of only said release magnet valve means, or simultaneous energization of said application and release valve means whereby to control the supply and the release of fluid under pressure to and from the brake cylinderand the maintenance of a pressure therein, and fluid pressure operated switch means of the self-lapping type operative according to the relation of r,-

a control fluid pressure and a pressure corresponding to that established in the brake cylinder for controlling said electron discharge-means so as to cause said application and release magnet valve means to operate to'control the 'supply and release of fluid under pressure to and from the brake cylinder so as to effect the establishment of a pressure inthe brake cylinder corresponding to the control fluid pressure supplied to the fluid pressure operated switch means. v t

3.'In a brake apparatus of the type having a brake cylinder operative. to efiect application of the brakes according to the pressure of fluid suppliedthereto, the combination of an application magnet valve device eifective when deenergized to out 01f the supply of fluid under pressureto the brake cylinder and operative whensenergized to cause fluid under pressure to be supplied to the brake cylinder, a release magnet valve deviceeffective whenideenergized to cause fluid under 55 pressure to be released from the brake cylinder and operative when energized to cause cut-off of the release of fluid under, pressure from the brake cylinder, a first electron discharge device having a control element and an anode-cathode circuitfor controlling energizationand deenergization of the application magnet valve device, a second electron discharge device having a control element and an anode-cathode circuit for controlling energization and deenergization of the,said release magnet valve device, and means for controlling the degree of biasing voltage impressed on the control elements of said discharge devices in a manner to cause said discharge devices to selectively effect the simultaneous deenergization of both said magnet valve devices, the simultaneous energization of both 'said magnet valve devices, or the simultaneous energization of' the release magnet valve ,device and deenergization of the application magnet valve device.

1 4. In a brakeapparatus of the type having a brake cylinder operative to effect application of the brakes according to the pressure of fluid supplied thereto, the combination of an application magnet valve device effective when deenergized to cut off the supply of fluid 'under pressure to the brake cylinder and operative when energized to cause fluid under pressure to be supplied to the brake cylinder, a release magnet valve device effective when deenergized to cause fluid under pressure to be released from the brake cylinder and operative when-energized to cause cut-off of the release of fluid under pressure from the brake cylinder, a first electron discharge device having a control element and an anode-cathode circuit for controlling energization and deenergization of the application magnet valve device, a second electron discharge device having a control element and an'anode-cathode circuit for controlling energization and deenergization of the said release magnet valve device, and a fluid pressure operated switch device of the self-lapping type operatively controlled according to the relation of a control fluid pressure and an opposing fluid pressure corresponding to the pressure established in the brake cylinder operative in response to an increase of the control fluid pressure to cause a biasing voltage on the control element to said discharge devices to be varied in a manner to cause sequential energization of the release magnet valve device and of the application magnet valve device, said fluid pressure operated switch device being effective in response to the build-up of a pressure in the brake cylinder'coresponding to that of an established control fluid pressure for so controlling the biasing voltage imposed on the said first electron discharge device as to cause deenergization of the application magnet valve device only.

5. In a brake system of the type having a brake cylinder operative to efiect application of the brakes according to the pressure of fluid supplied thereto, the combination of a fluid pressure operated switch device of the self-lapping type operatively controlled according to the relation of a control fluid pressure and an opposing fluid pressure corresponding to that established in the brake cylinder, said switch device comprising a first switch and a secondswitch adapted to be sequentially operated in the order named response to-an increase of the control fluid pressure and sequentially operated in the reverse order in response to a reduction of the control fluid pressure, an applicationmagnet operative when energized to cause fluid under pressureto be supplied to the brake cylinder and when deenergized to cause cut-off of the supply of fluid under pressure to the brake cylinder, a release magnet .eifective when deenergized to cause fluid under pressure to be released from the brake cylinder and operative when energized to cut off the release of fluid under pressure from the :brake cylinder, a first electron discharge device includinga controlmember and an anode-cathode circuit for controlling energization of thesaid release magnet, a second electron discharge device including acontrol member and an anode-cathode circuit for controlling energization of said application magnet,'a circuit including said first switch. of said fluid pressure operated switch device normally effective to impress a biasing voltage on the control member of said first electron discharge device to render'it nonconductive, said first switch being operative upon -an increase of the control fluid pressure to effect :75'a variation of the biasing voltage impressed on the control member whereby to render the said first electron discharge device conductive thereby to cause energization of said release magnet, a second circuit including the second switch of said fluid pressure operated switch device normally effective to impress a biasing voltage on the said second electron discharge device rendering it nonconductive, said second switch being operative in response to an increase of the control fluid pressure supplied to the fluid pressure operated switch device for efiecting a variation of the biasing voltage on the control member of said second electron discharge device thereby to cause energization of said application magnet, and being operative in response to the build-up of the opposing pressure corresponding to that established in the brake cylinder for restoring a biasing voltage on the control member of the said second electron discharge device to cause deenergization of the said application magnet, the pressure established in the brake cylinder being thereby maintained automatically in accordance with the pressure of the control fluid pressure.

6. In a brake system of the .type having a, brake cylinder operative according to the pressure of the fluid supplied thereto to eifect a corresponding degree of application of the brakes, the combination of an application magnet valve device effective when deenergized to cut off the supply of fluid under pressure to the brake cylinder and a operative when energized by a current exceeding a first certain value to cause fluid under pressure to be supplied to the brake cylinder, a release magnet valve device effective when deenergized to cause the release of fluid under pressure from the brake cylinder and operative when energized by a current exceeding a second certain value 10wer than the said first certain value for causin cut-off of the release of fluid under pressure from the brake cylinder, a single electron discharge device having a control element and an anode-cathode circuit for controlling energization of both said application and release magnet valve devices, and means for selectively applying difierent degrees of a biasing voltage on the control element of said electron discharge device whereby to correspondingly control the degree of current in the anode-cathode circuit to cause simultaneous deenergization of both said magnet valve devices, simultaneous energization of both of said magnet valve devices by a current exceeding said certain value, or simultaneous energization of both of said magnet valve devices by a current exceeding said second certain value but less than said first certain value.

7. In a brake system of the type having a brake cylinder operative according to the pressure of the fluid supplied thereto to effect a corresponding degree of application of the brakes, the cOmbination of an application magnet valve device efiective When deenergized to cut oil the supply of fluid under pressure to the brake cylinder and operative when energized by a current exceeding a first certain value to cause fluid under pressure to be supplied to the brake cylinder,-a release magnet valve device efiective when deenergized to cause the release of fluid under pressure from the brake cylinder and operative when energized by a current exceeding a second certain value lower than the said first certain value for causing cut-01f of the release of fluid under pressure from the brake cylinder, a circuit including a source of voltage for supplying energizing current to said application and release magnet valve devices, a single electron discharge device having a control element and an anode-cathode path interposed in said circuit, and means for selectively imposing different biasing voltages on the control element of said electron discharge device whereby to interrupt said circuit and efiect simultaneous deenergization of both the application and release magnet valve devices, or to control the current in the said circuit in a manner to cause simultaneous energization of both of the magnet valve devices by a current exceeding said certain degree, or simultaneous energization of both magnet valve devices by a current exceeding said second degree but less than said first degree.

CLAUDE M. HINES. 

